The Enlightenment critiques of religion were challenging enough, but they were answered
in due course more or less effectively. Here are three of the most important of them.

The challenge that there is after all no such a thing as
"religious knowledge"—a pattern of critique that we have
traced through Locke, Hume, Kant and beyond—produced a number of
creative replies.

The challenge that God was not a transcendent being but was entirely
immanent within the world historical process—a critique that we have
traced through Spinoza and especially Hegel—stimulated creative
responses in thinking about the nature of God and World.

The challenge that Jesus Christ was, after all, merely an inspired
human being—a critique present preeminently in deism and in Kant—produced
a variety of theological responses, some sympathetic and others less so,
but all of which enabled theology to continue to speak sensibly of Jesus
Christ as the center of the worshipping life of Christianity.

The 19th and early 20th centuries, following the pattern of the Enlightenment, produced
a series of enormously compelling, genuinely new perspectives on religion. But the
critiques implicit (and sometimes explicit) in these new perspectives were so forceful
that their reverberations are still being felt in contemporary theology to this day.

The most important of these new perspectives on religion can be
associated with the names of important European intellectuals—some of whom
were theologians—and will be described briefly in what follows. Some
caveats as we get started:

Keep in mind that some of these figures thought they were friends of religion, so that
the perspectives on religion that they offer were not intended by them to be devastating,
but only clarifying. Others can more properly be described as antipathetic toward religion
as they encountered it.

Also keep in mind that we are here summarizing just one sliver of each
person’s thought; we are bypassing enormously fruitful insights that
in many cases promise solutions to the very problems these thinkers
raise.

Finally, remember that this is not an exhaustive list of the perspectives on religion
generated in the 19th and early 20th centuries, but it is a list of most of the major
conceptual pieces of any interpretation of religion that has had much influence on
theology since the Enlightenment.

Some key phrases from Essence of Christianity that express
Feuerbach’s thesis:

"God is man, man is God." (p. xxxvi)

"Atheism is the secret of religion." (p. xxxvi)

"Religion itself, not indeed on the surface, but fundamentally, not in intention
or according to its own supposition, but in its heart, in its essence, believes in nothing
else than the truth and divinity of human nature." (p. xxxvi)

"Theology is Anthropology." (p. xxxvii)

"While reducing theology to anthropology, [I] exalt anthropology into theology,
very much as Christianity, while lowering God into man, made man into God."
(p. xxxviii)

"Religion takes the apparent, the superficial in Nature and humanity for the
essential, and hence conceives their true essence as a separate, special existence."
(p. xxxviii)

"Religion is the dream of the human mind…in these days, illusion
only is sacred, truth profane." (p. xxxix)

2. Principles of Feuerbach’s Thought

Humanity is wonderful beyond measure. It is wonderful enough to be worthy of the same
kind of lofty evaluation we accord to God in religion. Taking the wonder of humanity
seriously means that we ought to try to explain the world in terms of human
self-consciousness. When we do this, several conclusions follow.

First, religion can be exhaustively explained as the result of the projection of human
needs and desires onto the universe; it can only survive so long as the projective process
is unconscious.

Second, God can be exhaustively explained as the result of self-alienated
projection by humans of their own, infinite self-consciousness (cp. Hegel,
for whom humanity was the result of God’s self-alienation). Each attribute
of God expresses an aspect of the hope humans have to be free from their
limitations. So:

God’s holiness is a projection of human desire to be free of sin

God’s creativity is a projection of human failure to realize full
potential

God’s power is a projection of human sense of finitude and
vulnerability

God’s presence is a projection of human sense of loneliness and
mutual separation

God’s Trinitarian nature is a projection of the human need to be
whole through being an "I" participating in, though distinct
from, a "Thou"

The same method is applied to each of the doctrines of Christian theology: incarnation,
trinity, sacraments, prayer, the holy spirit, resurrection, etc.

The influence of Feuerbach is enormous. There are connections from his thought to
existentialism, atheism, psychology, history of religions, Marxism, etc., etc., etc.

Come back here soon for more on projection and Feuerbach's reversal of Hegel's
dialectic.

Marx owes his philosophical awakening to Feuerbach, whom he described by way of
Feuerbach's name as the "brook of fire" through which all had to pass in order
to lay hold of truth and freedom. From Feuerbach he learned that:

humans make religion in their own image;

they cling to religion so long as they feel the continued need to project themselves
onto the universe, so long as they love the illusion of their dreams more than the reality
of the waking world;

one of the signs of human maturity is the self-conscious attempt to overcome human
self-alienation, to be conscious of the projective impulse that gives rise to religion,
and then to leave religion, as such, behind.

But Marx also pushes further than Feuerbach to give a precise analysis of human
self-alienation, of the reasons why humans get involved in clinging to an illusory world
of projections in the first place. The problem, thinks Marx, is fundamentally political.

According to Marx, Feuerbach didn’t see something crucial that he
should have: the essence of the human, with which Feuerbach was so enamored,
is either a mere abstraction—theoretical and useless, and so just another
of Feuerbach’s projections—or it is the collection of actual living
situations in which humans find themselves. In the latter case, we can see
that humans and their self-alienation has to be understood in concrete
social, political terms.

With regard to religion, then, we don’t project an ideal, unalienated
realm in religion for nothing; we are desperately trying to deal with
ourselves in an unhappy, oppressed, dismal situation.

"The abolition of religion as the illusory happiness of the
people is required for real happiness. The demand to give up the
illusions about its condition is the demand to give up a condition that needs illusions…Thus
the criticism of heaven turns into the criticism of earth…the criticism of theology into
the criticism of politics." (On Religion, p. 42.)

Religion, therefore, must be understood in terms of the conditions that
produced (and produce) it. The details of a religion’s nature are the
result of social, and especially economic and political, forces, since these
forces give shape to human alienation in a particular place and time.

Marx is therefore a fierce critic of religion, though he is aiming not primarily at
religion as a cause of the problem, but only as a symptom that, once present, becomes part
of the corrupt socio-political order and only perpetuates the very problem it professes to
solve.

For Durkheim, religion is the reflection of society. Religious concerns
and values are socially sanctioned, extraordinarily expressive, and
powerfully controlling enactments—focused around sacred objects and places—of
the nature and values and concerns of society.

For Troeltsch, history is not guided in any particular way, for there is no
supernatural providence to guide it. History is the creation of human beings in groups,
and it will be what they make it. God is a reality for Troeltsch, and it is our spiritual
connection with God that gives rise to religions and to aspirations for history. But there
are no absolute standards for assessing historical developments, either within the church
or in society at large. History without absolutes must recognize the genuinely competitive
situation of religious pluralism. The religion will survive that is made to survive by its
adherents, for God is not active in the world in such a way as to define or defend the one
true faith.

Freud’s various theories about the origins and nature of religion are
presented in
Totem and Taboo, The Future of an Illusion, and Moses and Monotheism.

Freud's basic approach to religion is through his analysis of the psychological
structure of the human person, together with the assumption that if you can produce a
sufficient explanation of religion without invoking God, then you ought not invoke God.
The explanation of religion without reference to God does not imply that there is no God,
or that traditional theological assertions are necessarily false. But Freud argued against
those assertions independently. The real interest in Freud, and the real challenge to
theology, however, lies in his alternative explanation of religion. In this way, Freud is
an instance of a common challenge to Christianity, for many theorists of religion
(including Durkheim) offer explanations of the origin, efficacy and authority of religion
without supposing that the religions are correct in their assertions about ultimate
reality.

Profoundly indebted to Feuerbach, Freud argues that religion is the product of the
human desire to have wishes fulfilled; we project what we long to be the case. Religion is
thus illusion.

More than this, however, religion is dangerous. Consider the religious
belief in God as a perfect father—this is in compensation for our own
imperfect fathers. But then belief in God perpetuates the infantile longing
for a perfectly loving, comfortable parental figure. Religion, in other
words, retards human development. It also interferes with the larger goal of
attaining human maturity, because science aims to be clear about what is
real and what is illusion, and religion systematically blurs this
distinction.

The fundamental conclusion of these new perspectives on religion has only become
stronger since the time of these great thinkers, thanks especially to advances in the
human sciences and to the development of the neurosciences and such hybrid forms of
inquiry as sociobiology. And what is that fundamental conclusion?

The world and human beings can be adequately described without reference to God.
There is no place anywhere in the sphere of human concerns that is privileged in the sense
of needing God for its adequate explanation.

This means that these new insights into religion are, at one level, neutral to the
realities with which religion has to do. This is the case even though some theorists
rightly (though perhaps one-sidedly) point out the dangers of religion. For the first time
in the history of the West, a Godless universe was rendered rationally feasible and
atheism achieved the status of an intellectually serious option rather than a knee-jerk
reaction against a despised religious establishment. Theology has been profoundly changed
by this accomplishment of human reason.